Bugbear (8)
I believe the answer is:
bogeyman
'bugbear' is the definition.
(I know that bugbear can be written as bogeyman)
This is the entire clue.
(Other definitions for bogeyman that I've seen before include "Unpleasant character" , "Imaginary male feared by children" , "Scary personification?" , "Dreadful imaginary being" , "devil" .)